Population Dynamics of the Demosponge Aplysina Aerophoba (Nardo 1833) in the Mediterranean Sea Using MtDNA COI Gene

Aplysina Aerophoba is one of the most representative sponge species of the Mediterranean, while it is considered an indigenous species of the basin. Its importance lies not only in the fact that it is a main species of the benthic fauna, but many biomolecules with potential medicinal effects are extracted from it, which monopolized the interest of researchers. In the present research work, Aplysina Aerophoba population from the Aegean Sea was examined and compared with other Mediterranean populations, using the cytochrome oxidase (COI) subunit I gene, the use of which has a multitude of advantages. Regarding the population of the sponge from the Aegean Sea, it presented five different haplotypes, while a high diversity is observed based on the fixation index and molecular variance analysis. Among Mediterranean populations, there appears to be genetic differentiation between populations, while those from Italy and Spain showed a common haplotype. This result agrees with several works, which support the differentiation of populations of a species between the eastern and western Mediterranean Sea. This fact may be due to the seasonally changing climatic and geomorphological conditions of the basin. Moreover, by calculating the Tajima’s D index, the neutrality theory is confirmed, as the mutations do not change the allelic frequencies of the Aplysina Aerophoba populations under consideration. Finally, from the demographic study of the Aegean population, it emerged that it did not undergo any strong change in evolutionary time.

Key words: Aplysina Aerophoba, Mediterranean Sea, Populations genetics, COI, Demographics.